1. Field of the Invention
The present invention relates to an imaging device, an imaging device body, and a lens barrel that include an apodization filter.
2. Description of the Related Art
There is known an imaging device that includes an apodization filter (hereinafter, referred to as an APD filter) having optical characteristics in which light transmittance is reduced as a distance from an optical axis is increased (see JP2005-062733A corresponding to U.S. Pat. No. 7,099,555). The APD filter reduces the amount of light around only a blurred image (spotlight blurring or the like), which is out of focus, without reducing the amount of light around an image plane. Accordingly, the APD filter realizes a beautiful blur by applying gradation to the profile of a blurred image.
Since the APD filter has the above-mentioned optical characteristics, a light-reducing effect becomes great as the diaphragm value (F number) approaches an open value. For this reason, in JP2005-062733A, a substantial diaphragm value (T number), which is obtained by correcting an diaphragm value on the basis of the optical characteristics of the APD filter, is obtained and the determination of an imaging exposure (an imaging diaphragm value and an imaging shutter speed) is performed on the basis of the T number. In JP2005-062733A, a linear diaphragm type program diagram in which a diaphragm value continuously changes is used as a program diagram that is used for the determination of an imaging exposure.
A multiple-stage diaphragm type program diagram in which diaphragm values take discrete values is known as a program diagram other than the linear diaphragm type program diagram (see JP2007-274669A corresponding to U.S. Pat. Pub. No. 2007/212,055). The multiple-stage diaphragm type program diagram is used to mainly prevent an imaging diaphragm value from frequently changing due to a change in the brightness of a subject during a live view or video imaging.
Even in the imaging device disclosed in JP2005-062733A, it is considered that the determination of an imaging exposure is performed by using a multiple-stage diaphragm type program. diagram during a live view or video imaging. However, the correction of a diaphragm value based on the optical characteristics of the APD filter is performed as described above in JP2005-062733A. Accordingly, in the multiple-stage diaphragm type program diagram where diaphragm correction is reflected, an interval of diaphragm values is reduced as an diaphragm value approaches an open value.
Therefore, in a case in which a multiple-stage diaphragm type program diagram is used in an imaging device including an APD filter, an imaging diaphragm value frequently changes in accordance with a change in the brightness of a subject as an imaging diaphragm value approaches an open value. For this reason, unnatural flicker is generated.